As a conventional sample injection device for biochemical analysis of this type, the device disclosed in Patent Document 1 is known. In this device, a sample injection valve is provided in a carrier-liquid (eluant) channel which allows the carrier liquid to flow into a column by means of a pump, and the valve has a sample drawing position and a sample injection position.
In addition, it is necessary to wash the needle each time a new sample is drawn, and a needle washing unit for the washing is separately provided.
At the sample drawing position, the upper flow channel and the lower flow channel of the carrier-liquid channel are connected as a short circuit, and on the other hand, the sample loop is separated from the carrier-liquid channel, and the sample is drawn into the sample loop in this state.
At the sample injection position, the upper flow channel and the lower flow channel of the carrier-liquid channel are connected via the sample loop, and thereby the sample is injected into the flow of the carrier liquid.
In addition, after the sample is injected, the needle is moved to a needle washing position, which is separately provided, to undergo washing.